The answer is B because it is 1/3.
Answer:

Step-by-step explanation:
Given:
We took here a Right Angle Triangle,Δ ABC at angle B as 90°
Side opposite to angle A = a
Side opposite to angle B = b = Hypotenuse
Side opposite to angle C = c
To Find:
Sin A = ?
Solution:
Property of a Sine rule for a Right Angle Triangle.

∴ 
Answer:
a, d, e, g
I don't know if it's right :(
this was last year for me :(

Option ( C ) is the correct answer.
Answer:
sin⁴x - sin²x
sin²x(sin²x - 1)
(1 - cos²x)(1 - cos²x - 1)
(1 - cos²x)(-cos²x)
-cos²x + cos⁴x
cos⁴x - cos²x